Spinal implant system and methods of use

ABSTRACT

A bone fastener comprises a first member defining an implant cavity and a plurality of adjacent grooves. A first band is configured for disposal within the grooves. A second band is configured for disposal within the grooves. A second member is configured to penetrate tissue and includes a head engageable with the first band to provisionally connect the members. A first part is engageable with a spinal rod disposed with the implant cavity. A second part is attached with the first part and engageable with the second band to dispose the second band adjacent the first band to fix connection of the members. Implants, systems, instruments and methods are disclosed.

TECHNICAL FIELD

The present disclosure generally relates to medical devices for thetreatment of spinal disorders, and more particularly to a surgicalimplant system including a bone fastener and a related method.

BACKGROUND

Spinal pathologies and disorders such as scoliosis and other curvatureabnormalities, kyphosis, degenerative disc disease, disc herniation,osteoporosis, spondylolisthesis, stenosis, tumor, and fracture mayresult from factors including trauma, disease and degenerativeconditions caused by injury and aging. Spinal disorders typically resultin symptoms including deformity, pain, nerve damage, and partial orcomplete loss of mobility.

Non-surgical treatments, such as medication, rehabilitation and exercisecan be effective, however, may fail to relieve the symptoms associatedwith these disorders. Surgical treatment of these spinal disordersincludes correction, fusion, fixation, discectomy, laminectomy andimplantable prosthetics. As part of these surgical treatments, spinalconstructs such as vertebral rods are often used to provide stability toa treated region. Rods redirect stresses away from a damaged ordefective region while healing takes place to restore proper alignmentand generally support the vertebral members. During surgical treatment,one or more rods and bone fasteners can be delivered to a surgical site.The rods may be attached via the fasteners to the exterior of two ormore vertebral members. This disclosure describes an improvement overthese prior technologies.

SUMMARY

In one embodiment, a bone fastener is provided. The bone fastenercomprises a first member defining an implant cavity and a plurality ofadjacent grooves. A first band is configured for disposal within thegrooves. A second band is configured for disposal within the grooves. Asecond member is configured to penetrate tissue and includes a headengageable with the first band to provisionally connect the members. Afirst part is engageable with a spinal rod disposed with the implantcavity. A second part is attached with the first part and engageablewith the second band to dispose the second band adjacent the first bandto fix connection of the members. In some embodiments, implants,systems, instruments and methods are disclosed.

In one embodiment, the bone fastener comprises a first member definingan implant cavity and a plurality of adjacent grooves including a firstportion and a second portion having a greater diameter than the firstportion, A first band and a second band are configured for disposalwithin the grooves in an expanded configuration in the second portionand a contracted configuration in the first portion. A second member isconfigured to penetrate tissue and includes a head engageable with thefirst band to connect the members. A first part is engageable with aspinal rod disposed with the implant cavity. A second part is attachedwith the first part and engageable with the second band to fix thesecond band adjacent the first band. The head is engageable with thesecond part to limit relative movement in a single plane.

In one embodiment, the bone fastener comprises a first member definingan implant cavity and a plurality of adjacent grooves including a firstgroove, a second groove and a third groove. The second groove has agreater diameter than the first groove and the third groove. A firstexpandable band is configured for disposal within the grooves. A secondexpandable band is configured for disposal within the grooves. A secondmember is configured to penetrate tissue and includes a head engageablewith the first band for translation from the first groove to the secondgroove to provisionally connect the members. A first part is engageablewith a spinal rod disposed with the implant cavity. A second part isattached with the first part and engageable with the second band fortranslation from the third groove to the second groove such that thesecond band prevents the first band from translating back into thesecond groove to fix connection of the members for relative movement ina single plane. In some embodiments, the second band engages the firstband for translation to the second groove and restricts any furthertranslation of the first band to fix connection of first member tosecond member.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more readily apparent from thespecific description accompanied by the following drawings, in which:

FIG. 1 is a perspective cross section view of components of oneembodiment of a spinal implant system in accordance with the principlesof the present disclosure;

FIG. 2 is a perspective view of components of the system shown in FIG.1;

FIG. 3 is a perspective view of components of the system shown in FIG.1;

FIG. 4 is a perspective view of components of the system shown in FIG.1;

FIG. 5 is a perspective view of components of the system shown in FIG.1;

FIG. 6 is a perspective cross section view of components of oneembodiment of a spinal implant system in accordance with the principlesof the present disclosure;

FIG. 7 is a perspective cross section view of components of the systemshown in FIG. 6;

FIG. 8 is a perspective cross section view of components of the systemshown in FIG. 6;

FIG. 9 is a perspective cross section view of components of oneembodiment of a spinal implant system in accordance with the principlesof the present disclosure;

FIG. 10 is a perspective cross section view of components of the systemshown in FIG. 9;

FIG. 11 is a perspective cross section view of components of the systemshown in FIG. 9;

FIG. 12 is a perspective cross section view of components of the systemshown in FIG. 9;

FIG. 13 is a perspective cross section view of components of the systemshown in FIG. 9; and

FIG. 14 is a perspective cross section view of components of the systemshown in FIG. 9.

DETAILED DESCRIPTION

The exemplary embodiments of a surgical system and related methods ofuse disclosed are discussed in terms of medical devices for thetreatment of musculoskeletal disorders and more particularly, in termsof a spinal implant system including a bone fastener. In one embodiment,the present spinal implant system includes an implant comprising a bonefastener, such as, for example, a pedicle bone screw. In someembodiments, the systems and methods of the present disclosure areemployed with a spinal joint fusion or fixation procedure, for example,with a cervical, thoracic, lumbar and/or sacral region of a spine.

In some embodiments, the present spinal implant system comprises amodular bone screw having a restricted range of motion. In someembodiments, the present spinal implant system comprises a modularpedicle screw having a range of motion that is restricted to a singleplane. In some embodiments, the present spinal implant system comprisesmodular pedicle screw that allows for uni-axial functionality. In someembodiments, the present spinal implant system comprises a modular bonescrew system including a mechanism to resist and/or preventdisengagement of a retainer of a modular screw system. In someembodiments, the present spinal implant system comprises a modular bonescrew system including a screw shank, a receiver, a retainer, a part,such as, for example, a crown and a part, such as, for example, asleeve.

In some embodiments, the present spinal implant system comprises a bonescrew having a crown that comprises commercially pure titanium alloy (TiCP). In some embodiments, the crown is configured to provide an increasein axial grip on a spinal rod and an increase in flexion and/orextension strength. In some embodiments, the present spinal implantsystem comprises a bone screw having a sleeve that comprises cobaltchromium (CoCr). In some embodiments, the sleeve is configured toprovide an increase in the rigidity of the connection between the sleeveand the screw shank to facilitate manipulation of patient anatomy withthe bone screw.

In some embodiments, the present spinal implant system is employed witha method of attaching a head assembly with a screw shank including thesteps of translating a screw shank such that a retainer translates froma first chamber into a second chamber and expands then contracts toprovisionally capture the screw shank. In some embodiments, the methodincludes the step of, once the screw shank is provisionally captured,the compression member being translated towards an expansion memberforcing the expansion member from a third chamber into the secondchamber. In some embodiments, when the expansion member is fully in thesecond chamber it is allowed to expand. As such, the expansion memberallows for the compression member to pass through its inner diameter inthe expanded state. In some embodiments, the expansion member is sizedto prevent the retainer from disengaging from the first chamber. In someembodiments, the retainer positioned in the first chamber is preventedfrom expanding and retains the screw shank in the head assembly.

In some embodiments, the present spinal implant system is employed witha method including the steps of inserting a screw shank into a receiverto contact a retainer translating the retainer from a first chamber to asecond chamber. In some embodiments, the second chamber is oversizedallowing for expansion of the retainer as the screw shank is translatedinto the receiver. In some embodiments, the spinal implant systemcomprises a modular pedicle screw system having an additional expansionmember configured to block the second chamber after the screw shank isengaged with the receiver. In some embodiments, blocking of the secondchamber resists and/or prevents the retainer from migrating back intothe second chamber and resists and/or prevents disengagement of thecomponents of a pedicle screw.

In some embodiments, the present spinal implant system comprises amodular assembly consisting of a receiver, expansion member, retainerand compression member. In some embodiments, the receiver includesfirst, second, and third chambers. In some embodiments, the firstchamber is sized to be a close fit to a retainer member and the secondchamber is oversized to allow expansion of the retainer. In someembodiments, the expansion of the retainer allows a screw shank to passthrough the retainer. In some embodiments, a second expansion member isnested in an undersized third chamber, which causes the expansion memberto collapse, such as, for example, by a reduction in diameter. Theexpansion member contains an outer groove, which mates with the receiverto prevent unintentional disengagement. In some embodiments, theexpansion member in the relaxed state is sized with a diameter similarto the second chamber. In some embodiments, the spinal implant systemincludes a sleeve and a crown positioned above the expansion member.

In some embodiments, the spinal implant system comprises a modularsystem that includes a bone fastener including an array of members, suchas, for example, bone screw shafts that can be selectively coupled tomembers, such as, for example, receivers. In some embodiments, thespinal implant system comprises a selectively coupled bone fastener thatcan be assembled on a surgical table or in-situ. In some embodiments,the bone fastener is selectively coupled with a non-instrumented and/ormanual assembly. In some embodiments, the non-instrumented assemblycomprises manually engaging a screw shaft with a head/receiver of thebone fastener. In some embodiments, the non-instrumented assemblycomprises manually engaging the screw shaft in a pop-on engagement withthe head/receiver of the bone fastener. In some embodiments, a forcerequired to manually engage a screw shaft with a head/receiver of thebone fastener in a non-instrumented assembly is in a range of 2 to 50 N.In some embodiments, a force required to manually engage a screw shaftwith a head/receiver of the bone fastener in a non-instrumented assemblyis in a range of 5 to 10 N. In some embodiments, this configurationprovides manually engageable components of a bone fastener that areassembled without instrumentation, and subsequent to assembly, theassembled components have a selected pull-out strength and/or can bepulled apart, removed and/or separated with a minimum required force.

In some embodiments, the head assembly includes a ring disposed with animplant receiver connected with a screw shaft assembly. In someembodiments, the ring is configured to snap onto the screw shaftassembly. In some embodiments, the ring has a minimized thickness and/orheight to facilitate snapping the ring onto the screw shaft assembly. Insome embodiments, the force required to snap the ring onto the screwshaft assembly is in a range of 2 to 50 N. In some embodiments, theforce required to snap the ring onto the screw shaft assembly is in arange of 5 to 10 N.

In some embodiments, the bone fastener is configured for assemblywithout the use of an instrument, such as, for example, a practitioner,surgeon and/or medical staff utilizes their hands for assembly. In someembodiments, the system requires minimal force to attach an implantreceiver and a screw shaft assembly in-situ thereby reducing a pre-loadon the vertebrae, such as, for, example, the pedicle. In someembodiments, the bone fastener includes an expandable ring.

In some embodiments, the present disclosure may be employed to treatspinal disorders such as, for example, degenerative disc disease, discherniation, osteoporosis, spondylolisthesis, stenosis, scoliosis andother curvature abnormalities, kyphosis, tumor and fractures. In someembodiments, the present disclosure may be employed with other ostealand bone related applications, including those associated withdiagnostics and therapeutics. In some embodiments, the disclosed spinalimplant system may be alternatively employed in a surgical treatmentwith a patient in a prone or supine position, and/or employ varioussurgical approaches to the spine, including anterior, posterior,posterior mid-line, lateral, postero-lateral, and/or antero-lateralapproaches, and in other body regions. The present disclosure may alsobe alternatively employed with procedures for treating the lumbar,cervical, thoracic, sacral and pelvic regions of a spinal column. Thespinal implant system of the present disclosure may also be used onanimals, bone models and other non-living substrates, such as, forexample, in training, testing and demonstration.

The present disclosure may be understood more readily by reference tothe following detailed description of the embodiments taken inconnection with the accompanying drawing figures, which form a part ofthis disclosure. It is to be understood that this application is notlimited to the specific devices, methods, conditions or parametersdescribed and/or shown herein, and that the terminology used herein isfor the purpose of describing particular embodiments by way of exampleonly and is not intended to be limiting. In some embodiments, as used inthe specification and including the appended claims, the singular forms“a,” “an,” and “the” include the plural, and reference to a particularnumerical value includes at least that particular value, unless thecontext clearly dictates otherwise. Ranges may be expressed herein asfrom “about” or “approximately” one particular value and/or to “about”or “approximately” another particular value. When such a range isexpressed, another embodiment includes from the one particular valueand/or to the other particular value. Similarly, when values areexpressed as approximations, by use of the antecedent “about,” it willbe understood that the particular value forms another embodiment, It isalso understood that all spatial references, such as, for example,horizontal, vertical, top, upper, lower, bottom, left and right, are forillustrative purposes only and can be varied within the scope of thedisclosure. For example, the references “upper” and “lower” are relativeand used only in the context to the other, and are not necessarily“superior” and “inferior”.

As used in the specification and including the appended claims,“treating” or “treatment” of a disease or condition refers to performinga procedure that may include administering one or more drugs to apatient (human, normal or otherwise or other mammal), employingimplantable devices, and/or employing instruments that treat thedisease, such as, for example, microdiscectomy instruments used toremove portions bulging or herniated discs and/or bone spurs, in aneffort to alleviate signs or symptoms of the disease or condition.Alleviation can occur prior to signs or symptoms of the disease orcondition appearing, as well as after their appearance. Thus, treatingor treatment includes preventing or prevention of disease or undesirablecondition (e.g., preventing the disease from occurring in a patient, whomay be predisposed to the disease but has not yet been diagnosed ashaving it). In addition, treating or treatment does not require completealleviation of signs or symptoms, does not require a cure, andspecifically includes procedures that have only a marginal effect on thepatient. Treatment can include inhibiting the disease, e.g., arrestingits development, or relieving the disease, e.g., causing regression ofthe disease. For example, treatment can include reducing acute orchronic inflammation; alleviating pain and mitigating and inducingre-growth of new ligament, bone and other tissues; as an adjunct insurgery; and/or any repair procedure. Also, as used in the specificationand including the appended claims, the term “tissue” includes softtissue, ligaments, tendons, cartilage and/or bone unless specificallyreferred to otherwise.

The following discussion includes a description of a surgical systemincluding a bone fastener, related components and methods of employingthe surgical system in accordance with the principles of the presentdisclosure. Alternate embodiments are also disclosed. Reference is madein detail to the exemplary embodiments of the present disclosure, whichare illustrated in the accompanying figures. Turning to FIGS. 1-8, thereare illustrated components of a spinal implant system 10.

The components of spinal implant system 10 can be fabricated frombiologically acceptable materials suitable for medical applications,including metals, synthetic polymers, ceramics and bone material and/ortheir composites. For example, the components of spinal implant system10, individually or collectively, can be fabricated from materials suchas stainless steel alloys, commercially pure titanium, titanium alloys,Grade 5 titanium, super-elastic titanium alloys, cobalt-chrome alloys,superelastic metallic alloys (e.g., Nitinol, super elasto-plasticmetals, such as GUM METAL®), ceramics and composites thereof such ascalcium phosphate (e.g., SKELITE™), thermoplastics such aspolyaryletherketone (PAEK) including polyetheretherketone (PEEK),polyetherketoneketone (PEKK) and polyetherketone (PEK), carbon-PEEKcomposites, PEEK-BaSO₄ polymeric rubbers, polyethylene terephthalate(PET), fabric, silicone, polyurethane, silicone-polyurethane copolymers,polymeric rubbers, polyolefin rubbers, hydrogels, semi-rigid and rigidmaterials, elastomers, rubbers, thermoplastic elastomers, thermosetelastomers, elastomeric composites, rigid polymers includingpolyphenylene, polyimide, polyimide, polyetherimide, polyethylene,epoxy, bone material including autograft, allograft, xenograft ortransgenic cortical and/or corticocancellous bone, and tissue growth ordifferentiation factors, partially resorbable materials, such as, forexample, composites of metals and calcium-based ceramics, composites ofPEEK and calcium based ceramics, composites of PEEK with resorbablepolymers, totally resorbable materials, such as, for example, calciumbased ceramics such as calcium phosphate, tri-calcium phosphate (TCP),hydroxyapatite (HA)-TCP, calcium sulfate, or other resorbable polymerssuch as polyaetide, polyglycolide, polytyrosine carbonate,polycaroplaetohe and their combinations.

Various components of spinal implant system 10 may have materialcomposites, including the above materials, to achieve various desiredcharacteristics such as strength, rigidity, elasticity, compliance,biomechanical performance, durability and radiolucency or imagingpreference. The components of spinal implant system 10, individually orcollectively, may also be fabricated from a heterogeneous material suchas a combination of two or more of the above-described materials. Thecomponents of spinal implant system 10 may be monolithically formed,integrally connected or include fastening elements and/or instruments,as described herein.

Spinal implant system 10 includes a spinal implant, such as, forexample, a bone fastener 180. Bone fastener 180 comprises a member, suchas, for example, a screw shaft assembly 12 connectable with a member,such as, for example, a head assembly 13 in a configuration having arange of motion that is restricted to a single plane. In someembodiments, engagement of head assembly 13 and screw shaft assembly 12allows for relative movement in a single plane forming a uni-axial bonefastener 180.

Head assembly 13 includes a band, such as, for example, a retaining ring36 configured for provisional capture of screw shaft assembly 12 and/orfixed connection of the components of bone fastener 180, as describedherein. Head assembly 13 includes a band, such as, for example, a ring44 configured for disposal in a contracted orientation and an expandedinterference orientation adjacent to ring 36 to facilitate fixedconnection of the components of bone fastener 180. In some embodiments,screw shaft assembly 12 and head assembly 13 are assembled in situ orprior to implant to form bone fastener 180, as described herein.

Head assembly 13 includes a receiver 14. Receiver 14 extends along anddefines an axis X1. Receiver 14 includes a pair of spaced apart arms 16,18 that define an implant cavity 20 therebetween configured for disposalof a component of a spinal construct, such as, for example, a spinal rod(not shown).

Arms 16, 18 each extend parallel to axis X1. In some embodiments, arm 16and/or arm 18 may be disposed at alternate orientations, relative toaxis X1, such as, for example, transverse, perpendicular and/or otherangular orientations such as acute or obtuse, coaxial and/or may beoffset or staggered. Arms 16, 18 each include an arcuate outer surfaceextending between a pair of side surfaces. At least one of the outersurfaces and the side surfaces of arms 16, 18 have at least one recessor cavity therein configured to receive an insertion tool, compressioninstrument and/or instruments for inserting and tensioning bone fastener180. In some embodiments, arms 16, 18 are connected at proximal anddistal ends thereof such that receiver 14 defines a closed spinal rodslot. In some embodiments, a spinal rod may be monolithically formedwith receiver 14 or pre-assembled with receiver 14.

Cavity 20 is substantially U-shaped. In some embodiments, all or only aportion of cavity 20 may have alternate cross section configurations,such as, for example, closed, V-shaped, W-shaped, oval, oblongtriangular, square, polygonal, irregular, uniform, non-uniform, offset,staggered, and/or tapered. Receiver 14 includes an inner surface 22. Aportion of surface 22 includes a thread form 24 located adjacent arm 16and a thread form 26 located adjacent arm 18. Thread forms 24, 26 areeach configured for engagement with a coupling member, such as, forexample, a setscrew (not shown), to retain the spinal rod within cavity20. In some embodiments, surface 22 may be disposed with the couplingmember in alternate fixation configurations, such as, for example,friction fit, pressure fit, locking protrusion/recess, locking keywayand/or adhesive. In some embodiments, all or only a portion of surface22 may have alternate surface configurations to enhance engagement withthe spinal rod and/or the setscrew, such as, for example, rough,arcuate, undulating, mesh, porous, semi-porous, dimpled and/or textured.In some embodiments, receiver 14 may include alternate configurations,such as, for example, closed, open and/or side access. In someembodiments, screw shaft assembly 12 is manually engaged with headassembly 13 in a non-instrumented assembly, as described herein, suchthat removal of head assembly 13 from screw shaft assembly 12 canwithstand a clamp force applied from the coupling member.

Receiver 14 includes portion 28, as shown in FIG. 6. Portion 28 includesa surface 30. Surface 30 defines a cavity, such as, for example, agroove 34. Groove 34 is configured for disposal of ring 36. In someembodiments, groove 34 extends about all or a portion of surface 30.Groove 34 includes a diameter D1. Ring 36 includes a circumference thatdefines an opening, such as, for example, a gap. In some embodiments,the gap is sized such that the gap has a thickness that is less than theheight and the width. In some embodiments, the gap is sized to allowring 36 to pass though a bottom of receiver 14 by contractingcircumferentially.

Portion 28 includes a surface 40, as shown in FIG. 6. Surface 40 definesa cavity, such as, for example, a groove 42. Groove 42 is configured fordisposal of ring 44. Ring 44 includes a surface 46 that defines an outergroove 48 configured for engagement with a surface of groove 42, asdescribed herein. Ring 44 includes a circumference that extends betweenends of ring 44. In some embodiments, the ends define an opening, suchas, for example, a gap. In some embodiments, the gap is sized such thatthe gap has a thickness that is less than the height and the width. Insome embodiments, the gap is sized to allow ring 44 to engage surface 40by contracting circumferentially.

Groove 42 includes a projection 50. Projection 50 is configured forengagement with surface 46 of outer groove 48, as shown in FIG. 7.Projection 50 retains ring 44 within groove 42. Projection 50 isconfigured to resist and/or prevent disengagement of ring 44 from groove42. Ring 44 is disengageable from groove 42 upon engagement with a part,such as, for example, a sleeve 100, which causes surface 46 to disengagefrom projection 50 and drives ring 44 from groove 42, as describedherein. Groove 42 includes a diameter D2. In some embodiments, diameterD1 is equal to diameter D2, as shown in FIG. 6. In some embodiments,diameter D1 and diameter D2 are different. In some embodiments, surface40 retains ring 44 within groove 42 and groove 42 does not includeprojection 50.

Receiver 14 includes a portion 60, as shown in FIG. 7. Portion 60includes a surface 62. Surface 62 defines a cavity, such as, forexample, a groove 64 configured for disposal of ring 36 and/or ring 44.In some embodiments, groove 64 extends about all or a portion of surface40. Groove 64 includes a circumferential channel 66 that accommodatesexpansion of ring 36 and/or ring 44, as described herein. Groove 64includes a diameter D3. Diameter D3 is greater than diameter D1 and/ordiameter D2. Diameter D3 is sized to allow for expansion of ring 36and/or ring 44 therein. Grooves 34, 42, 64 are disposed in a serialorientation along axis X1, as shown in FIG. 1. In some embodiments,grooves 34, 42, 64 are disposed in spaced apart relation.

A surface 68 is disposed between groove 64 and groove 34, as shown inFIG. 7. Surface 68 is disposed at an angle relative to axis X1 to definea ramp 69. Ramp 69 is selectively inclined to facilitate translation ofring 36 between groove 34 and groove 64, as described herein. In oneexample, ring 36 is engaged with screw shaft assembly 12 for translationsuch that ring 36 slides along ramp 69, which directs and/or guides ring36 from groove 34 into groove 64, and expands into a provisional captureorientation with screw shaft assembly 12. In another example, ring 36 isengaged with ring 44 for translation such that ring 36 slides along ramp69, which directs and/or guides ring 36 from groove 64 into groove 34,and contracts for fixed connection of the components of bone fastener180 including permanent capture of head assembly 13 and screw shaftassembly 12. In some embodiments, surface 68 is oriented substantiallyperpendicular to axis X1.

Ring 36 is resiliently biased to a contracted and/or capture orientationwithin groove 34, as shown in FIG. 9, and expandable to an expandedorientation within groove 64, as shown in FIGS. 11 and 12, forprovisional capture of screw shaft assembly 12 with head assembly 13, asdescribed herein. Ring 36 is expandable from the contracted and/orcapture orientation to the expanded orientation for assembly of screwshaft assembly 12 with head assembly 13, as shown and described forexample with regard to FIGS. 9-14.

Ring 44 is disposable in a contracted orientation within groove 42, asshown in FIGS. 9-13, and resiliently biased to an expanded interferenceorientation within groove 64, as shown in FIG. 14. In the interferenceorientation, ring 44 is disposed in channel 66 and adjacent to ring 36for abutting and/or contacting engagement therewith to resist and/orprevent translation of ring 36 from groove 34 into groove 64, and fixedconnection of the components of bone fastener 180 including permanentcapture of head assembly 13 and screw shaft assembly 12, as describedherein.

Receiver 14 includes a surface 70. Surface 70 defines a slot 72. Slot 72is configured for disposal of a part, such as, for example a crown 80and a part, such as, for example, sleeve 100. In some embodiments, allor only a portion of surface 70 may have alternate surfaceconfigurations, such as, for example, rough, arcuate, undulating, mesh,porous, semi-porous, dimpled and/or textured.

Crown 80 is configured for disposal within cavity 20 and slot 72. Crown80 includes a circumferential wall 82 having an end surface 84 and anend surface 86, as shown in FIG. 2. Surface 84 is configured to defineat least a portion 88 of cavity 20. Portion 88 is defined by an outersurface 90 that defines a curved portion of crown 80 configured forengagement with a spinal implant, such as, for example, a spinal rod.Surface 90 is configured to provide an axial grip with a spinal implant,such as, for example, a spinal rod. Crown 80 is configured to provideflexion and/or extension strength to facilitate movement of the spinalrod. In some embodiments, crown 80 includes and/or is fabricated fromcommercially pure titanium. In some embodiments, all or only a portionof surface 90 may have alternate cross section configurations, such as,for example, oval, oblong triangular, square, polygonal, irregular,uniform, non-uniform, offset, staggered, and/or tapered.

Surface 84 defines a circumferential flange 200. Receiver 14 includes anundercut surface that defines a groove 202. Flange 200 is configured fordisposal with groove 202, as shown in FIG. 6. Engagement of flange 200with the undercut surface that defines groove 202 retains crown 80 withreceiver 14 in a first orientation adjacent ring 44 when ring 44 isdisposed in groove 42. Translation of crown 80, as described herein withregard to FIGS. 12-14, into a second orientation moves ring 44 fromgroove 42.

Surface 86 defines a pair of recesses 92 circumferentially disposedabout crown 80. Recesses 92 are configured to facilitate engagement ofcrown 80 with a part, such as, for example, sleeve 100, as describedherein. Recess 92 is substantially U-shaped. The wall portions ofsurface 86 that define recess 92 taper inwardly to capture sleeve 100,as described herein. In some embodiments, recess 92 may have alternateconfigurations, such as, for example, closed, V-shaped, W-shaped, oval,oblong triangular, square, polygonal, irregular, uniform, non-uniform,offset, staggered, flared and/or non-tapered. In some embodiments,surface 86 defines one or a plurality of recesses 92.

Sleeve 100 includes a circumferential wall 102 having an end surface 104and an end surface 106, as shown in FIG. 3. Surface 104 includes a pairof flared projections 108. Projections 108 are configured for a snap-fitengagement with the wall portions of surface 86 that define recess 92,as shown in FIG. 4, to fixedly attached sleeve 100 with crown 80. Sleeve100 is configured to provide rigidity in the connection of sleeve 100and screw shaft assembly 12 to facilitate manipulation of patientanatomy, for example, vertebrae. In some embodiments, sleeve 100includes and/or is fabricated from chromium cobalt. In some embodiments,projection 108 may engage recess 92 to attach sleeve 100 with crown 80in various fixation configurations, such as, for example, pop-fit,friction fit, pressure fit, locking keyway and/or adhesive. In someembodiments, projections 108 may have alternate configurations, such as,for example, closed, V-shaped, W-shaped, oval, oblong triangular,square, polygonal, irregular, uniform, non-uniform, offset, staggered,and/or tapered. In some embodiments, surface 104 defines one or aplurality of projections 108.

Sleeve 100 is configured for translation within slot 72 along surface70. Translation of sleeve 100 within slot 72 causes surface 106 toengage ring 44. Surface 106 is disposed adjacent ring 44 such that axialtranslation of sleeve 100 displaces ring 44 from groove 42. Ring 44 isdisengageable from groove 42 upon engagement with sleeve 100, whichcauses surface 46 to disengage from projection 50 and drives ring 44from groove 42. As such, ring 44 is movable between the contractedorientation and the expanded interference orientation in groove 64, asdescribed herein, to prevent migration of ring 36 from groove 34 intogroove 64 for fixed connection of the components of bone fastener 180.Surface 106 is positioned with ring 44 to resist and/or preventdisplacement of ring 44 from channel 66.

Screw shaft assembly 12 includes shaft 181 and head 182. Shaft 181 isconfigured to penetrate tissue, such as, for example, vertebral tissue.In some embodiments, shaft 181 includes an outer surface having anexternal thread form. In some embodiments, the external thread form mayinclude a single thread turn or a plurality of discrete threads. Head182 includes a tool engaging portion 184 configured to engage a surgicaltool or instrument, as described herein. In some embodiments, portion184 includes a hexagonal cross-section. In some embodiments, portion 184may have alternative cross-sections, such as, for example, rectangular,polygonal, hexalobe, oval, or irregular. Head 182 includes a surface 186that defines a plurality of ridges 188 to improve purchase of head 182with crown 80. In some embodiments, head 182 includes an outer surface190 having planar surfaces or flats and/or arcuate surfaces.

Surface 190 defines protrusion, such as, for example, a ridge 194. Ridge194 extends circumferentially about head 182. Ridge 194 includes asurface 196 and a surface 198 configured for engagement with ring 36. Ashead 182 axially translates along receiver 14, surface 196 engages ring36 causing ring 36 to translate into groove 64 to an expandedorientation, as described herein. As head 182 translates further intoreceiver 14, ring 36 passes over ridge 194 and resiliently contractsabout head 182 within channel 66 to provisionally capture screw shaftassembly 12, as shown in FIG. 12. As head 182 translates in an oppositedirection, surface 198 engages ring 36 to drive ring 36 from groove 64into groove 34, as described herein. Surface 198 is configured to resistand/or prevent disengagement of ring 36 from groove 34 for permanentcapture of head assembly 13 and screw shaft assembly 12 in aconfiguration having a range of motion that is restricted to a singleplane. In some embodiments, head 182 includes planar side surfaces toenable uni-axial movement when the components of bone fastener 180 areassembled.

In some embodiments, screw shaft assembly 12 is manually engageable withhead assembly 13 in a non-instrumented assembly, as described herein. Insome embodiments, manual engagement and/or non-instrumented assembly ofhead assembly 13 and screw shaft assembly 12 includes coupling withoutuse of separate and/or independent instrumentation engaged with screwshaft assembly 12 components to effect assembly. In some embodiments,manual engagement and/or non-instrumented assembly includes apractitioner, surgeon and/or medical staff grasping head assembly 13 andscrew shaft assembly 12 and forcibly assembling the components. In someembodiments, manual engagement and/or non-instrumented assembly includesa practitioner, surgeon and/or medical staff grasping head assembly 13and screw shaft assembly 12 and forcibly snap fitting the componentstogether, as described herein. In some embodiments, manual engagementand/or non-instrumented assembly includes a practitioner, surgeon and/ormedical staff grasping head assembly 13 and screw shaft assembly 12 andforcibly pop fitting the components together and/or pop fitting headassembly 13 onto screw shaft assembly 12, as described herein. In someembodiments, a force in a range of 2-50 N is required to manually engagehead assembly 13 and screw shaft assembly 12 and forcibly assemble thecomponents. For example, a force in a range of 2-50 N is required tosnap fit and/or pop fit assemble head assembly 13 and screw shaftassembly 12. In some embodiments, a force in a range of 5-10 N isrequired to manually engage head assembly 13 and screw shaft assembly 12and forcibly assemble the components. For example, a force in a range of5-10 N is required to snap fit and/or pop fit assemble head assembly 13and screw shaft assembly 12. In some embodiments, this configurationprovides manually engageable components that are assembled withoutinstrumentation, and subsequent to assembly, the assembled componentshave a selected pull-out strength and/or can be pulled apart, removedand/or separated with a minimum required force. In some embodiments,receiver 14 may be disposed with head 182 in alternate fixationconfigurations, such as, for example, friction fit, pressure fit,locking protrusion/recess, locking keyway and/or adhesive.

In some embodiments, spinal implant system 10 comprises a spinal implantkit, as described herein, which includes a plurality of screw shaftassemblies 12 and/or head assemblies 13. Screw shaft assembly 12 and/orhead assembly is configured for selection such that the components ofbone fastener 180 are interchangeable in a configuration having a rangeof motion that is restricted to a single plane.

In assembly, operation and use, spinal implant system 10, similar to thesystems and methods described herein, includes a screw shaft assembly 12for connection with a head assembly 13, and is employed with a surgicalprocedure for treatment of a spinal disorder affecting a section of aspine of a patient, as discussed herein. Spinal implant system 10 isemployed with a surgical procedure for treatment of a condition orinjury of an affected section of the spine.

In some embodiments, a screw shaft assembly 12 is selected from a kit ofa plurality of screw shaft assemblies 12 for interchangeable connectionwith head assembly 13 to comprise a bone fastener having uni-axialmovement and/or a range of motion that is restricted to a single plane.In some embodiments, the kit of screw shaft assemblies 12 includes avariety of screw shaft assemblies having different movementconfigurations when assembled with an interchangeable head assembly 13,such as, for example, multi-axial movement, sagittal angulationmovement, fixed axis movement, mono-axial movement and/or uni-planarmovement.

In some embodiments, head assembly 13 includes receiver 14 assembledwith crown 80, sleeve 100, ring 44 and ring 36, as shown in FIGS. 5-8.In some embodiments, crown 80 is engaged with sleeve 100 by connectionof projections 108 with recesses 92, as described herein. In someembodiments, ring 44 is initially disposed with groove 42 in acontracted orientation, as shown in FIG. 7. In some embodiments, ring 36is initially disposed with groove 34 in a contracted orientation, asshown in FIG. 8.

Screw shaft assembly 12 is manually engageable, as described herein,with head assembly 13, as shown in FIGS. 9-14. Head assembly 13 isassembled with screw shaft assembly 12 by translating receiver 14, in adirection shown by arrow A in FIG. 9. Engagement of head 182 withreceiver 14 causes surface 196 to engage ring 36. Surface 196 causesring 36 to translate ring 36, in a direction shown by arrow B in FIG.10, such that ring 36 is positionable and allowed to expand into groove64 to an expanded orientation, as described herein.

Diameter D3 of groove 64 is larger than diameter D1 of groove 34 toallow ring 36 to expand into channel 66. Engagement of surface 196 withan inner surface of ring 36 causes ring 36 to expand and slide alongramp 69 into channel 66. As head 182 translates further into receiver14, ring 36 passes over ridge 194 and resiliently contracts about head182 within channel 66 to provisionally capture screw shaft assembly 12,as shown in FIG. 12.

Screw shaft assembly 12 is translated, in a direction shown by arrow Cin FIG. 12, to seat screw shaft assembly 12 with receiver 14.Translation of head 182 causes surface 198 to engage ring 36. Surface198 causes ring 36 to translate, in a direction shown by arrow D in FIG.13, to drive ring 36 from groove 64 into groove 34. Ring 36 axiallytranslates along receiver 14 and/or slides along ramp 69 into groove 34.In some embodiments, surface 198 is positioned with ring 36 to resistand/or prevent displacement of ring 36 from groove 34.

Crown 80 and sleeve 100 are manipulated, for example, via engagement bya surgical instrument to translate crown and sleeve 100, in a directionshown by arrow E in FIG. 14. Surface 106 engages ring 44 such thatsurface 46 disengages from projection 50 and ring 44 is displaced fromgroove 42, as shown in FIG. 14. Ring 44 translates into groove 64 andresiliently expands into channel 66 to an expanded, interferenceorientation, as described herein. Ring 44 is oriented for abuttingand/or contacting engagement with ring 36 to resist and/or preventtranslation of ring 36 from groove 34 into groove 64, and fixedconnection of the components of bone fastener 180 including permanentcapture of head assembly 13 and screw shaft assembly 12 in aconfiguration having a range of motion that is restricted to a singleplane, for example, in a uni-axial movement configuration. Surface 106is positioned with ring 44 to resist and/or prevent displacement of ring44 from channel 66.

In use, for treatment of a spinal disorder, bone fastener 180 includingassembled screw shaft assembly 12 and head assembly 13 can be threadedand engaged with tissue. In some embodiments, bone fastener 180 isdisposed adjacent vertebrae at a surgical site and is manipulated todrive, torque, insert or otherwise connect shaft 181 with vertebrae inconnection with a surgical procedure, as described herein. In someembodiments, crown 80 includes a surface fabricated from commerciallypure titanium for engagement with a spinal rod disposed with receiver 14to provide an axial grip and flexion and/or extension strength tofacilitate movement of the spinal rod. In some embodiments, sleeve 100includes a surface fabricated from chromium cobalt to provide rigidityin the connection of sleeve 100 and screw shaft assembly 12 tofacilitate manipulation of vertebrae.

In some embodiments, spinal implant system 10 includes an agent, whichmay be disposed, packed, coated or layered within, on or about thecomponents and/or surfaces of spinal implant system 10. In someembodiments, the agent may include bone growth promoting material, suchas, for example, bone graft to enhance fixation of the fixation elementswith vertebrae. In some embodiments, the agent may be HA coating. Insome embodiments, the agent may include one or a plurality oftherapeutic agents and/or pharmacological agents for release, includingsustained release, to treat, for example, pain, inflammation anddegeneration.

In some embodiments, the use of microsurgical and image guidedtechnologies may be employed to access, view and repair spinaldeterioration or damage, with the aid of spinal implant system 10. Thecomponents of spinal implant system 10 can be made of radiolucentmaterials such as polymers. Radiomarkers may be included foridentification under x-ray, fluoroscopy, CT or other imaging techniques.

In some embodiments, spinal implant system 10 can include one or aplurality of bone fasteners 180 such as those described herein and/orfixation elements, which may be employed with a single vertebral levelor a plurality of vertebral levels. In some embodiments, bone fasteners180 may be engaged with vertebrae in various orientations, such as, forexample, series, parallel, offset, staggered and/or alternate vertebrallevels. In some embodiments, bone fasteners 180 may be configured asmulti-axial screws, sagittal angulation screws, pedicle screws,mono-axial screws, uni-planar screws, fixed screws, anchors, tissuepenetrating screws, conventional screws, expanding screws. In someembodiments, bone fasteners 180 may be employed with wedges, anchors,buttons, clips, snaps, friction fittings, compressive fittings,expanding rivets, staples, nails, adhesives, posts, connectors, fixationplates and/or post.

It will be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplification of thevarious embodiments. Those skilled in the art will envision othermodifications within the scope and spirit of the claims appended hereto.

1-20. (canceled)
 21. A bone fastener comprising: a first member defininggrooves and a projection; a first band; a second band defining a recessconfigured for disposal of the projection; a second member engageablewith the first band to provisionally connect the members; a first part;and a second part attached with the first part and being engageable withthe second band to remove the projection from the recess and dispose thesecond band adjacent the first band to fix connection of the members.22. A bone fastener as recited in claim 21, wherein the recess isconfigured for disposal of the projection to resist movement of thesecond band relative to the first member.
 23. A bone fastener as recitedin claim 21, wherein the second member is configured to penetrate tissueand includes a head that is engageable with the first band toprovisionally fix the members.
 24. A bone fastener as recited in claim21, wherein the first member comprises an inner surface that defines thegrooves, the projection extending outwardly from the inner surface. 25.A bone fastener as recited in claim 24, wherein the recess is configuredfor disposal of the projection to resist movement of the second bandrelative to the inner surface.
 26. A bone fastener as recited in claim24, wherein the second part includes a circumferential wall engageablewith the inner surface and the second band, the wall including at leastone flared projection.
 27. A bone fastener as recited in claim 24,wherein the grooves include a first groove, a second groove and a thirdgroove that are circumferentially disposed with the inner surface andalong a longitudinal axis thereof.
 28. A bone fastener as recited inclaim 27, wherein the third groove has a larger diameter relative to thefirst groove and the second groove.
 29. A bone fastener as recited inclaim 21, wherein the first part includes a circumferential wallengageable with the inner surface, the wall including at least onerecess.
 30. A bone fastener as recited in claim 21, wherein the fixedconnection of the members includes relative movement in a single plane.31. A bone fastener as recited in claim 21, wherein the members areconnected in a uni-axial screw configuration.
 32. A bone fastener asrecited in claim 21, wherein the second part interfaces with the secondmember to restrict relative movement between the members to a singleplane.
 33. A bone fastener as recited in claim 21, wherein the secondpart includes a pair of flared projections engageable with a pair ofrecesses of the first part.
 34. A bone fastener as recited in claim 21,wherein the first band is expandable between a provisional captureorientation and an expanded orientation, and the second band isexpandable between a contracted orientation and an interferenceorientation to fix connection of the members.
 35. A bone fastenercomprising: a first member defining grooves and a projection, thegrooves including a first portion and a second portion having a greaterdiameter than the first portion; a first band and a second bandconfigured for disposal within the grooves in an expanded configurationin the second portion and a contracted configuration in the firstportion, the second band defining a recess configured for disposal ofthe projection when the bands are in the contracted configuration toresist movement of the second band relative to the first member; asecond member engageable with the first band to connect the members; afirst part; and a second part attached with the first part and beingengageable with the second band to remove the projection from the recessand dispose the second band adjacent the first band.
 36. A bone fasteneras recited in claim 35, wherein the second member is engageable with thesecond part to limit relative movement in a single plane.
 37. A bonefastener as recited in claim 35, wherein the first portion includes afirst groove and a third groove that are circumferentially disposed withan inner surface of the first member, and the second portion includes asecond groove disposed between the first groove and the third groove.38. A bone fastener as recited in claim 35, wherein the grooves aredisposed in a serial orientation along a longitudinal axis of the firstmember.
 39. A bone fastener as recited in claim 35, wherein the firstband is expandable between a provisional capture orientation and anexpanded orientation, and the second band is expandable between acontracted orientation and an interference orientation to fix connectionof the members.
 40. A bone fastener comprising: a first member defininga first groove, a second groove and a third groove, the second groovehaving a greater diameter than the first groove and the third groove,the first member comprising a projection positioned within the thirdgroove; a first expandable band; a second expandable band defining arecess configured for disposal of the projection; a second memberengageable with the first band for translation from the first groove tothe second groove to provisionally connect the members; a first part;and a second part attached with the first part and engageable with thesecond band for translation to remove the projection from the recess asthe second band translates from the third groove to the second groovesuch that the second band prevents the first band from translating backinto the second groove to fix connection of the members for relativemovement in a single plane.